Two new species of Passalus Fabricius (Coleoptera: Passalidae) from the western Brazilian Amazon with comments on the taxonomic limits of the subgenera

Passalus Fabricius, 1792 is the largest genus of Passalidae and presents great diversity in South America, mainly in the Amazon region. Currently this complex and heterogeneous genus is subdivided into three subgenera: P. (Pertinax) Kaup, 1869, P. (Mitrorhinus) Kaup, 1871, and P. (Passalus). Herein, two new species of Passalus from the western region of the Brazilian Amazon, a diverse but poorly studied area, are described and illustrated. The new species Passalus (Pertinax) deuterocerus sp. nov. and Passalus (Passalus) cleidecostae sp. nov. are compared with similar species occurring in nearby regions. Also, the diagnostic characters used to define the subgenera and sections of Passalus are summarized.